Temperature factor The third factor for good fermentati […]
The third factor for good fermentation is temperature. Yeasts are greatly affected by temperature; if they are too cold, they become dormant, too hot (more than 10 ° F above normal), and indulge in fermentation spree that usually cannot be cleaned up by regulation. High temperatures will promote fusel production-fusel may have a harsh taste similar to solvents. Many of these debris are esterified during the secondary fermentation process, but large amounts of these esters can dominate the flavor of beer. Due to the high temperature fermentation, beer that tastes bananas excessively is an example of high esters.
High temperatures can also lead to excess diacetyl. A common mistake in homemade beer is to ferment the yeast when the wort is not sufficiently cooled and is relatively warm. If the wort is, for example, 90 ° F, when the yeast is fermented and slowly cooled to room temperature during the initial fermentation, the early stage will produce more diacetyl groups than the yeast can reabsorb in the second stage. In addition, primary fermentation is an exothermic process. Just because of the activity of the yeast, the internal temperature of the fermentor can be 10F higher than the environmental conditions. Therefore, it is very important to maintain the fermentor at an appropriate temperature range. Therefore, under normal vigorous fermentation, even if the beer is warmer than the surrounding environment, the results are in line with expectations.
If you have no way to keep the fermentor cool, then brewing in summer is undoubtedly a problem. My friend Scott showed me a clever trick, he will immerse (incompletely immerse) the fermentor in the spare bathtub in the summer. Even if the temperature is 90 degrees Celsius, the water in the bathtub will slowly warm up during the day, and at night, even if the temperature drops to 45 degrees Fahrenheit, the water will slowly cool. The fermentation temperature is between 60-70 F, and the beer becomes great. I myself used this method in the laundry tub and achieved great success. You can regularly add ice to the water to keep it in a temperature range suitable for beer. If you have no way to keep the fermentation tank cool and the beer temperature exceeds 70-75F (21-24C), the beer may produce odors, such as fruity taste, phenolic or similar solvent taste and aroma.